Easy Access is a Firefox addon which allows you to launch programs or system commands directly from the Firefox status bar.
Install the addon and you'll see an icon appear on the right side of the status bar. Click this, a drop-down menu gives you some default entries - Notepad, Paint, Calculator, My Computer, Switch Profile - and you can launch any of them with a click.
There's also a "Manage Your Own Easy Access" option which allows you to add further programs of your own.
And you can add any of all of your program icons to the left of the Easy Access icon, ensuring you'll be able to launch any of them with a single click.
As launchers go, Easy Access isn't exactly sophisticated. You can't group your icons, for instance, or reorder them, and they're not particularly configurable, either.
Still, if you always have a Firefox window open then the addon does do exactly what its name suggests, giving you very easy access to whatever tools and applications you need.